Lebanese President Michel Sleiman cautioned Shiite Muslim group Hezbollah on Friday over its militants' intervention on the side of the regime in the conflict in neighbouring Syria.
"The resistance is more noble and more important than anything, and should not get bogged down in the sands of dissension, whether in Syria or Lebanon," he said in a statement, referring to Hezbollah's traditional focus on fighting Israel.
"The resistance has fought and liberated (Israeli-occupied southern Lebanon) because it acts for a national cause and not a confessional one," Sleiman added.
The statement came as the militant group battled Syrian rebel fighters in the central town of Qusayr near the border, where Syrian troops launched an assault on Sunday.
The fighting has left dozens of Hezbollah fighters dead, according the Syrian Observatory for Human Rights and sources close to the group.
Lebanon is officially neutral in the conflict, but the fighting has exacerbated tensions among its myriad of religious and ethnic communities.
Hezbollah and its allies have backed the regime of President Bashar al-Assad in its efforts to crush the uprising that began in March 2011.
But Lebanon's opposition parties largely support the Sunni-led rebellion against the Syrian regime.
Hezbollah has acknowledged that its fighters are inside Syria, and several Lebanese Sunni clerics have urged members of their community to join the conflict on the side of the rebels.
Sleiman, elected in 2008, is seen as a neutral figure who sides with neither camp. His comments Friday were his first on Hezbollah's role in Syria.
They come on the eve of Liberation Day, which marks the Israeli army's withdrawal from southern Lebanon in 2000 after 22 years of occupation.
Hezbollah chief Hassan Nasrallah is expected to deliver an anniversary speech on Saturday.
The Shiite group's intervention in the conflict has drawn international criticism, particularly from the United States, which blacklists Hezbollah as a terrorist organisation.
On Tuesday, President Barack Obama called Sleiman to discuss Hezbollah's intervention.
"We have condemned and condemn again Hezbollah's direct intervention in the assault on Qusayr where Hezbollah's fighters are playing a significant role in the regime's offensive," White House spokesman Jay Carney said after the call.
"Hezbollah's occupation of villages in Syria and its support for the regime and pro-Assad militias exacerbates and inflames regional sectarian tensions and perpetuates the regime's campaign of terror against the Syrian people".
As the group's role in Syria grows, France announced on Wednesday that it would propose that Hezbollah's military wing be added to the European Union's blacklist of "terrorist" organisations.